Rocker arm operating and timing apparatus for internal combustion engine



Dec. 20, 1966 w. J. RIFFE' ROCKER ARM OPERATING AND TIMING APPARATUS FORINTERNAL COMBUSTION ENGINE Filed Oct. 20, 1964 2 Sheets-Sheet lINVENYZOR.

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Dec. 20, 1966 w, RIFFE 3,22,504

ROCKER ARM OPERATING AND TIMING APPARATUS V FOR INTERNAL COMBUSTIONENGINE Filed 001:. 20, 1964 2 Sheets-Sheet 2 FIG: 42

IN VEN TOR.

A TTUfi/VEYS.

William J/Fiffe, v

United States Patent s 292 604 ROCKER ARM oPERATING AND TIMING APPARATUSFOR INTERNAL COMBUS- TION ENGINE William Joseph Riffe, 217 Bickley Road,Glenside, Pa. 19038 Filed Oct. 20, 1964, Ser. No. 405,197 6 Claims. (Cl.123-90) This invention relates to internal combustion engines and, moreparticularly, to a novel rocker arm operating apparatus which permits achange in timing of the operation of the intake and exhaust valves inrelation to movement of the pistons while the engine is running.

In general, this invention teaches the replacement of the standard,generally vertically positioned push rods by carn equipped rotatingshafts, said shafts having means rocker arms.

Overhead Camshafts, when used to operate the intake and exhaust valves,are driven by gearing or chains from the crankshaft located externallyto the block. The required series of separate, multiple gears or chainsare heavy and require that the engine be enlarged to accommodate thismechanism which, in the push rod system, is substantially mounted withinthe block. Also, slippage and play of the driving gears and chainsreduces the overall efficiency of the engine.

In the push rod-rocker arm system, high speed operation with highefliciency is prevented by physical distortion of the push rods andtheir tendency to float in relation to their operating cams. This causesthe rocker arms and valves to open or close at the wrong time.

Therefore, it is the primary object of this invention to avoid theinefiiciencies and limitations of both the overhead camshaft system androcker arm-push rod system of valve operation identified above bysubstituting substantially, a rotating cam equipped shaft in place ofeach push rod in the engine block.

It is a further object of this invention to provide in an apparatussatisfying the above objects means for mechanically or hydraulicallyadjusting the timing of the rocker arm operation in relation to thespeed of the engine while the engine is running.

Further objects of this invention are the provision of apparatus meetingthe above objects and, in addition, providing means for quick and easyreplacement of the rocker arm cam when a different lift or dwellcharacteristic is desired Without substantial disassembly of the engine.The apparatus of this invention makes possible a wide choice of camprofiles and eliminates thrust or side play on the valve assemblyassociated with a sharp profile cam. The apparatus of this invention isadvantageously stiff with no whip or hysterisis of shaft and valve lashis minimal because shaft expansion can be absorbed by supporting bearingmembers. With elimination of pushrods and lifter-tappet assemblies, thereciprocating mass is small enough so that high speeds are possiblewithout appreciable valve float.

These objects and other attendant advantages of this invention willbecome more apparent from the description set forth hereinbelow and fromthe drawings attached hereto wherein FIGURE 1 is a schematic view inside elevation of a 3,292,604 Patented Dec. 20, 1966 preferred form ofrocker arm actuating shaft and its drive system shown in relation to theengine block;

FIGURE 2 is a partial schematic perspective view of one form of therocker arm operating cam and shaft;

FIGURE 3 is a partial schematic perspective view of a modified form ofthe rocker arm operating cam and shaft as shown in FIGURE 2;

FIGURE 4 is a view in side elevation and partly in section showing thepreferred form of the mechanical adjustable rocker arm actuatingapparatus of this invention; and

FIGURE 5 is a view in side elevation and partly in section illustratingone form of the hydraulically adjustable rocker arm operating apparatusof this invention.

This invention in part may generally be described as the substitution ofa plurality of cam equippedrotating shafts in place of the reciprocatingpush rods so that the rocker arms continue their standard operation ofcontrolling the spring biased valves by reciprocating while movingacross the rotating inclined cam surfaces. The cam equipped, rotatingshafts are further provided with means for independently rotating thecam forward or behind the driving shaft thereby changing the valveactuating position or timing in relation to the position of a particularpiston in the engine.

The following description is directed to the specific forms of theinvention illustrated in the drawings and is not intended to limit thescope of the invention itself which may be practiced in a wide varietyof forms and arrangements.

Referring preliminarily to FIGURE 1 of the drawings, a standard engineblock is indicated by the dot and dash lines and identified by thenumeral 10. A geared shaft 12, which drives a series of cam equippedshafts 20, is supported along its length by a plurality of bearings 14and is located within the engine block in the recess which presentlycontains the conventional push rod camshaft. Typically, the geared shaft12 is provided with a series of preferably helical gears 15a one ofwhich is shown in FIGURE 1, and at the forward end extends through thefront of the engine block 10 where a spur gear 16 is mounted. Spur gear16 meshes with drive gear 17 which may be mounted on the crankshaft (notshown) or may be an idler gear between said crankshaft gear and gear 16.Geared shaft 12 is mounted substantially parallel to the crankshaft orparallel to the longitudinal axis of the engine and earn shafts 20, oneof which is shown in FIGURE 1, are mounted generally vertically orforming a V in relation to shaft 12 as seen from the front. As a resultof the meshing of gears 17 and 16, geared shaft 12 rotates in apredetermined timed relationship with the crankshaft.

A rocker arm operating shaft 20 is mounted Within the block at everypoint where a push rod is located in the standard push rod engine so asto operate at least one rocker arm in the engine head and therebycontrol the operation of at least one valve. Shaft 20 is provide-d witha plurality of bearings 22 distributed along its length to hold theshaft rigid in relation to the block 10 and geared shaft 12. Helix gear15 preferably is attached to the lower end of shaft 20 so as to meshwith a similar gear 15a on shaft 12 whereby shaft 20 is caused to rotatein timed relation to shaft 12. Shaft 20 is positioned in a planeperpendicular to that of shaft 12.

The upward end of shaft 20 extends out of the engine block and isequipped with a disc shaped cam 24 which has an inclined surface 26 uponwhich presses the tip 29 of a standard rocker arm 28. The rocker arm ismounted on the engine block 10 in the standard way so that it pivots ona center fulcrum base and presses down at one end not shown, against avalve stem (either intake or exhaust) opening the valve against a springmounted on the valve stem and engine block. The rocker arm reciprocatesas indicated by the arrows when tip 29 is raised. The valve engaging end(not shown) displaces a valve 'downward and open when tip 29 is raised.'When cam 24 rotates so that the surface 26 presents the lower end 260:,then rocker arm tip 29 moves downward allowing 'the rocker arm toreciprocate and control movement of the valve or valves. It is possibleto mount more than one rocker arm on a single cam 24 or mount aplurality of cams on a single shaft 20.

A modified form of the rocker arm cam 24 shown in FIGURES 1 and 2 is theassembly shown in FIGURE 3. In this form, cylinder cam 30 is fixedlymounted on shaft 20 and is provided with an axial bore 32 in which astem 34 is mounted for vertical movement. A roller 36 is attached tostem 34 by pin 37 and moves along the inclined surface 31 of cam 30under pressure of rocke-r arm tip 29. A spring 35 is provided to dampenany movement of stem 34 in the axial direction. rotates, roller 37 ridesalong the inclined surface 31 cansing stud 34 and rocker arm end 29 toreciprocate. The prime advantage of the assembly of FIG. 3 is that theroller dispenses with the small amount of friction existing in thedesign shown in FIG. 2.

This invention further includes means for adjusting the position ortiming of the rocker arm operating cam in relation to the location ormovement of the piston in the related cylinder. It is well known that athigher vr.p.m. or engine speed the timing of the opening and closing ofthe intake and exhaust valves will, for greater efficiency, bedilTere-nt from the settings for normal speeds. The apparatus disclosedherein provides automatic means for mechanically or hydraulicallycausing the cam to assume a new position relative to the rocker armwhile the engine is running thereby adjusting the engine for greaterefliciency at each range of speed.

The preferred form of the mechanically adjustable rocker arm actuatingassembly is shown in FIG. 4. In this form, geared shaft 40, serving thesame function as shaft 12 in the FIG. 1 embodiment, is equipped withhelix gear 42 which meshes with helix gear 44 formed on the surface of atubular shaft 46. In place of the solid shaft 20 of the FIG. 1embodiment, shaft 46 has an axial bore 48 extending the full length ofthe shaft.

Mounted for limiited axial movement with shaft 46 is a piston 50 havingat the lower end, as shown in FIG. 4, a round cam 54 and a flange 52 bywhich a spiral spring 56 is held captive against theannular base 47 ofouter shaft 46. At the upward end, piston 50 has an axial bore 58 inwhich is mounted cam stem 60 sup- As cam 30 porting cam 62. A screw 63extends-through cam 62 and cam portion 62a and is threaded into stem 60.The stem 60 is splined at 60a to provide ready replacement of cam 62 foranother cam having a different profile. A knurled knob 64 is aflixed toscrew 62. A retaining stud 46a; fixed in shaft 46 and engaged in slot60b at stem 60, prevents axial movement of cam stem 60 but allows thestem and cam 62 to rotate or revolve relative to shaft 46.

An axially directed, outer shaft slot 49 is formed in the wall of shaft46 to receive a protruding piston aligning key 51 attached to piston 50whereby piston 50 is caused to rotate with shaft 46 but is freeto moveaxially in response to a force exerted on round cam 45.

An inclined piston adjusting slot 55 is formed in the wall of piston 50adjacent the bore 58 and a cam roller or wedge 60c, attached to cam stem60, is positioned within slot 55. Upon movement of piston 50 in theaxial or upward direction, the walls defining inclined slot 55 move soas to cause the roller 60c held captive therein to move to the left asshown in FIG. 4. As a result, cam stem 60 and cam 62 are rotated in aclockwise direction as seen from the top of the form shown in FIG. 4.Such movement, distinct and separate from the rotation of shaft 46,would cause rocker arm tip 70 to descend as the cam 62 moved to presentits lower surface. Similarly, when piston 50 is caused to descendrelative to shaft 46, slot 55 causes roller 600 to move to the right asshown in FIGURE 4 thereby causing the cam 62 to rotatecounter-clockwise.

A cam adjusting rod 72 is shown at thebottom of FIG.

4 and consists of rod 73 mounted parallel to geared shaft 40 and havingan enlarged cam collar 74 positioned thereon. When the rod 72 is movedto the left as shown in FIG. 4, piston 50 is caused to move upwardagainst spring 56 thereby causing cam 62 to rotate clockwise as viewedfrom the top. When rod 72 is moved to the right, piston 50 descends byvirtue of spring 56 causing the stem 60 and cam 62 to rotatecounter-clockwise as viewed from above. Movement of cam adjusting rod 72may be controlled by the operator from within the vehicle or may. beoperatively set within the engine compartment while Shaft is providedwith an axial bore 84 which extends a portion of the length of the shaftfrom the top.

Mounted within bore 84 for axial movement relative thereto is piston 86which is equipped with a protruding alignment stud 87 mounted withinaxially directedslot 88 formed in the wall of shaft 80. Stud 87 and slot88 cause piston 86 to rotate with shaft 80 but allow limited axialmovement relative thereto. A stem 90 is mounted for limited rotarymovement within a bore 86a in piston 86 and supports at its upper endcam 92 held thereon by threaded screw 94. A rocker arm tip 105 presseson cam 92. A retaining stud 80a locks the stem 90 to shaft 80 preventingaxial movement of the stem relative to the shaft but allowing limitedrotation thereof. A spring 96 is compressed between piston 86 a and theenlarged portion 90a of the stem 90. A protruding roller 90c attached tostem 90 is positioned within inclined slot 99 formed in the wall ofpiston 86 causing the stem 90 and cam 92 to rotate when piston 86 movesin a vertical direction.

An oil chamber 100 is formed within shaft 80 beneath piston assembly 86and oil ports 102 formed in shaft 80 allow engine oil flowing throughcam oil gallery 104 to pass into chamber 100 and hydraulically affectthe position of piston 86 against spring 96 within bore 84.

In operation, this form of the apparatus of this invention functionssubstantially as follows. When the speed or r.p.m. of the engine buildsup, oil pressure is increased by the standard oil pump and that pressureis reflected in the pressure of the oil in oil gallery 104 and inchamber 100. The increased oil pressure presses against the bottom ofpiston 86 causing it to rise thereby causing the inclined walls of slot99 to displace the roller 90c to the left as-showniin FIG. 5 androtating the cam clockwise as seen from thetop. Similarly, upon adecrease in oil pressure acting upon piston 86 in oil chamber 100,spring 96 forces piston 86 downwards,

rotating cam 92 in the counter-clockwise direction. The

movement of piston assembly 86 axially may be set by In this form, shaft80 is r substituting a spring 96 of varying compression strengths.

Pressure in oil gallery 104 and in chamber 100 may be controlled by acheck valve (not shown) preferably located at the exit end of thegallery.

Of course, like the mechanical adjusting assembly shown in FIG. 4,adjustment of the rocker arm cams can occur while shaft 46 of the FIG. 4embodiment and shaft 80 of the FIG. 5 embodiment are rotating andcausing the rocker arms to reciprocate. It is one of the uniqueadvantages of this invention that adjustment to the most efficient valvesetting or opening time may be continually made for the particularengine speed then employed.

It should also be understood that the basic cam shaft of this inventioncan be positioned so that the cam works directly upon the valve stemthereby eliminating the necessity for a rocker arm. All other apparatusof this invention would function in the same manner as if a rocker armwere present.

It is another advantage of this invention that the proposed apparatuscan be utilized in the existing engine block design with only minorchanges necessary to the head and block assemblies. The cost ofmanufacture of the geared drive shaft and the geared cam shaftassemblies will be competitive to the cost of the presently usedcamshafts and lift rods.

Although this invention has been described with reference to specificforms and embodiments thereof, it will be apparent to those skilled inthe art that various changes other than those referred to above may bemade in the form of the apparatus, that equivalent elements may besubstituted for those illustrated in the drawings, that parts may bereversed, and that certain features of the invention may be used toadvantage independently of the use of other features, all within thespirit and scope of the invention as defined in the appended claims.

Having thus described my invention, I claim:

1. In an internal combustion engine having a crankshaft and a cylindervalve controlled by a rocker arm, rocker arm operating apparatuscomprising a first shaft mounted for rotation having a cam surfacepositioned proximate one end and extending about the axis of said shaft,said cam surface extending generally along a plane disposed at an acuteangle relative to the axis of said shaft, said shaft having externalgear means positioned proximate the opposite end thereof,

a member extending upwardly through the center of said cam surface andmounted for shifting movement vertically relative to said cam surface,said member being urged downwardly by said rocker arm, roller means onsaid member in rolling contact with the cam surface whereby said rollermeans moves over the surface of the cam as said first shaft rotates,causing the rocker to reciprocate in a vertical direction, and

a geared shaft mounted for rotation and positioned substantiallyperpendicular to the first shaft proximate the gear means, said gearedshaft being driven in timed relation to the crankshaft and having gearsto engage the gears on the first shaft whereby the cam surface is causedto rotate in timed relation to the crankshaft thereby imparting areciprocating motion to the rocker arm.

2. In a standard internal combustion engine having a piston, cylinder,crankshaft, cylinder valve and valve operating rocker arm, apparatus foroperating and varying the timing of the rocker arm in relation to pistonmovement comprising a first shaft mounted for rotation having aninternal axial bore and means mounted thereon for causing shaft torotate in timed relation to the reciprocatory movement of a piston,

a second shaft mounted within the bore of said first shaft and attachedthereto so that the second shaft rotates with the first shaft and canmove axially independent of the first shaft,

a cam member attached to both shafts by means whereby the cam memberrotates with the first shaft and revolves as the second shaft movesaxially in relation to the first shaft, said cam member having a camsurface formed within a plane extending transverse to the axis of thesecond shaft and in contact with the rocker arm so that upon rotation ofthe cam the rocker arm reciprocates in a vertical direction, and

means for causing said second shaft to move in an axial direction whilesaid first shaft rotates whereby the relative position of the camsurface in contact with the rocker arm can be varied in relation to therelative position of the piston.

3. The apparatus as defined in claim 2 wherein means causing axialmovement of the second shaft comprises a rod mounted substantiallyperpendicular to the second shaft, said rod having a cam surface thereonin contact with the distal end of said shaft,

a spring mounted on said shaft urging said shaft into contact with saidcam surface whereby movement of the rod in one direction causes the camsurface to push the shaft axially in one direction and movement of therod in the opposite direction causes the spring to push the shaft in theopposite direction.

4. The apparatus as defined in claim 2 wherein means causing the axialmovement of the second shaft comprises a source of oil under pressure,said pressure increasing as the piston reciprocates at a higher speed,

means directing the fluid to a position within the bore of the firstshaft and against the second shaft so as to cause the second shaft tomove axially from an initial position as the pressure increases therebycausing the cam surface to revolve in one direction, and

spring means for returning the second shaft to the initial position andthereby causing the cam surface to revolve in the opposite directionupon the decrease in oil pressure.

5. The apparatus as defined in claim 2 further includa geared shaftmounted substantially perpendicular to the first shaft and having gearmeans for rotating the first shaft, said geared shaft connected to thecrankshaft for rotation therewith in timed relation.

6. In a standard internal combustion engine, a hydraulic adjustablerocker arm operating apparatus comprising a generally verticallypositioned tubular shaft mounted for rotation, said shaft being rotatedin timed relation to the crankshaft in general and the adjacent pistonin particular,

a piston assembly mounted within the shaft, said assembly having a studextending into an elongated axial slot in the tubular wall of the shaftthereby causing the piston assembly to rotate with the shaft butallowing axial movement of the assembly relative to the shaft,

a cam stem mounted within a bore extending inwardly from the upward endof the piston assembly, said ca m stem having a roller stud extendinginto an elongated slot in the piston assembly and positioned obliquelyto the axis of the piston assembly thereby causing the cam stem torotate with the piston assembly and allowing the stem to revolverelative to the piston assembly as the assembly moves axially, said camstem having locking means preventing axial movement of the cam stemrelative to the shaft,

7 S a cam surface mounted on the cam stem, said surface References Citedby the Examiner forming generally a plane transverse to the axis UNITEDSTATES PATENTS of the cam stern and providing a surface upon which therocker arm presses so that upon rotation of the earn, the rocker arm iscaused to reciprocate 5 1,029,764 6/1912 Opsahl. 1,147,313 7/1915Desort.

in a vertical direction, 11632223 6/1927 a spring pressing the pistonassembly downwardly i 2,225,102 12/1940 Daub -90 the shaft, and 2, 0,787 12/1942 Kales 12390 means for directing engine oil under pressureinto a 3 60 6/1954 Lantz 123-90 compartment in the shaft beneath thepiston assem- 10 FOREIGN PATENTS bly whereby upon higher engine speedthe increase in oil pressure causes the piston assembly to rise in theshaft therehy revolving the cam surface and MARK NEWMAN, PrimaryExaminen changing the position of the rocker arm relative the positionof the adjacent piston in its cycle at 15 AL LAWRENCE SMITH, Examiner.any one instant of time.

229,033 2/ 1925 Great Britain.

1.IN AN INTERNAL COMBUSTION ENGINE HAVING A CRANKSHAFT AND A CYLINDERVALVE CONTROLLED BY A ROCKER ARM, ROCKER ARM OPERATING APPARATUSCOMPRISING A FIRST SHAFT MOUNTED FOR ROTATION HAVING A CAM SURFACEPOSITIONED PROXIMATE ONE END AND EXTENDING ABOUT THE AXIS OF SAID SHAFT,SAID CAM SURFACE EXTENDING GENERALLY ALONG A PLANE DISPOSED AT AN ACUTEANGLE RELATIVE TO THE AXIS OF SAID SHAFT, SAID SHAFT HAVING EXTERNALGEAR MEANS POSITIONED PROXIMATE THE OPPOSITE END THEREOF, A MEMBEREXTENDING UPWARDLY THROUGH THE CENTER OF SAID CAM SURFACE AND MOUNTEDFOR SHIFTING MOVEMENT VERTICALLY RELATIVE TO SAID CAM SURFACE, SAIDMEMBER BEING URGED DOWNWARDLY BY SAID ROCKER ARM, ROLLER MEANS ON SAIDMEMBER IN ROLLING CONTACT WITH THE CAM SURFACE WHEREBY SAID ROLLER MEANSMOVES OVER THE SURFACE OF THE CAM AS SAID FIRST SHAFT ROTATES, CAUSINGTHE ROCKER TO RECIPROCATE IN A VERTICAL DIRECTION, AND A GEARED SHAFTMOUNTED FOR ROTATION AND POSITIONED SUBSTANTIALLY PERPENDICULAR TO THEFIRST SHAFT PROXIMATE THE GEAR MEANS, SAID GEARED SHAFT BEING DRIVEN INTIMED RELATION TO THE CRANKSHAFT AND HAVING GEARS TO ENGAGE THE GEARS ONTHE FIRST SHAFT WHEREBY THE CAM SURFACE IS CAUSED TO ROTATE IN TIMEDRELATION TO THE CRANKSHAFT THEREBY IMPARTING A RECIPROCATING MOTION TOTHE ROCKER ARM.